In the past, such systems, when erected to form a three-dimensional structure, have had the disadvantage of requiring the tubes and connectors to be disconnected from the outer periphery of the structure to the inside, for example when it has been desired to modify the configuration of an inner portion of the structure. This has been because the ends of the tubes have had to be seated on the corresponding arms by longitudinal movement of the tubes to insert the arms into the open ends of the tubes. Thus, when it has been necessary to reconfigure an internal area of the structure, because of the rigid, overall construction of the structure, it has been necessary to start at the outside of the structure and remove tubes and connectors in sequence until they have been "eaten away" to the area where reconfiguration is desired. The time and effort required to do this may be excessive.
Another difficulty with such systems has been the difficulty in constructing a suitable connector since such connectors have an unusual shape, with arms extending outwardly in many different directions. Thus, manufacturing such connectors has conventionally required a relatively complicated mold or relatively complicated machining operations, in this latter case with much wastage of material.
The systems of the present invention provide demountable structures which have many applications, for example to form rigid three-dimensional display sections for museums, trade shows and the like.
Canadian patent No. 1,017,525 of Florence issued Sept. 20, 1977 describes a conventional system of connectors and tubes of the type in question. Other patents of general background interest describing connector assemblies for tubular structures are Canadian patents Nos. 743,695 of Gatterre issued Oct. 4, 1966 and 321,611 of Ragsdale issued April 1932.
It is an object of the present invention to provide a system of connectors and elongated tubes for forming a rigid three-dimensional rectangular structure, which system permits reconfiguration of internal portions of the structure without the need of having to dismantle outer portions of the structure.
It is a further object of the present invention to provide connectors for such a system which may be economically and simply cut from extrusions.